Wednesday, June 14, 2006

Before we went to the Yankees-Red Sox game last week, my friend Jaime sent me an e-mail about the location of our seats, which were relatively close to right field and within foul ball range. "You can bring a glove to protect me," he wrote.

"You'll recall that I don't have any depth perception," I wrote back. "I won't be any use to you."

I've been using that line for a long time to explain my failures at sports, driving, appreciation for M.C. Escher... I have a lazy right eye, and I never developed stereoscopic vision. I was excited to see my disability get the Oliver Sacks literary treatment in this week's issue of the New Yorker (not available online).

Sacks points out that those without stereoscopic vision often don't know it until an opthamologist or optometrist points it out, which was the case for me. The eye doctor gave me a few depth perception tests (pictures of objects at various distances, the Brock test of beads on a string) and then finally asked, "Are you just guessing about your answers?" I didn't realize that there was something I wasn't getting. Sacks writes that most people depend on a combination of binocular and monocular clues to judge distance:

There are, of course, many other ways of judging depth: occlusion of distant objects by closer objects, perspective (the fact that distant objects appear smaller), shading (which delineates the shape of objects), "aerial" perspective (the blurring and bluing of more distant objects by intervening air), and, most important, motion parallax--the change of spatial relationships as we move our heads. All these cues, acting in tandem, can give a vivid sense of reality and space and depth. But the only way to actually perceive depth rather than judge it is with binocular stereoscopy.

I became that kid in gym class who's pathetically untalented but loves to explain the reason why (I always felt superior to the hypoglycemic kids, who should have known better how to control themselves). The gym teachers didn't care (nor should they have). In seventh grade, we learned how to play tennis at the same time that our Spanish class was performing "Blanca Nieve." I played La Bruja and my friend Meg played El Espejo. Faced with my failure at the end of the play, I had to throw an apple at Meg, "break" her, and fall to my knees and exclaim that I had become "inutil" ("useless"--why was this the adjective we chose?) Tennis lessons thus became drama class, in which I'd try to hit the ball and yell "inutil, inutil, inutil!" In retrospect, it seems either really sad or really funny that I made it through gym class yelling that I was useless over and over again.

Because it gives me the opportunity to explain away things that I'm not very good at doing, I've never thought about what it would be like to have depth perception. Sacks writes,

There may even be certain advantages to monocular vision, as when photographers nad cinematographers deliberately renounce their binocularity and stereoscopy by confining themselves to a one-eye, one-lens view, the better to frame and compose their pictures. And those who have never had stereopsis but manage well without it may be hard put to understand why anyone should pay as much attention to it. Errol Morris, the filmmaker, was born with strabismus, and subsequently lost all the vision in one eye, but feels he gets along perfectly well. "I see things in 3-D," he said. "I move my head when I need to--parallax is enough. I don't see the world as a plane. He joked that he considered stereopsis no more than a "gimmick" and found my interest in it "bizarre."

I tried to argue with him on the special character and beauty of stereopsis. But one cannot convey to the stereo-blind what stereopsis is like; the subjective quality, the quale, of stereopsis is unique and no less remarkable than that of color. However brilliantly a person with monocular vision may function, he or she is, in this one sense, totally lacking.

The second half of the article is about a woman who lacked stereoscopy but developed it after she received special prismatic glasses and practiced depth perception exercises. In her correspondence with Sacks, she explained how her new experience with stereoscopy felt like being on drugs or being in a fun house, but she was eager to try out everything she missed. Sacks includes part of her correspondence:

When I was eating lunch, I looked down at my fork over the bowl of rice and the fork was poised in the air in front of the bowl. There was space between the fork and the bowl. I had never seen that before. ... I kept looking at a grape poised at the edge of my fork. I could see it in depth....Today, I was walking by a complete horse skeleton in the basement of the building where I work, when I saw the horse's skull sticking out so much, that I actually jumped back and cried out.

More than anything, I'm moved that this woman found a correspondent as genuinely interested in depth perception as Oliver Sacks. It's a wonderful article.

I can totally remember that!!! Actually, I remember us being particularly excited about using the word "inutil" and quite proud of ourselves for using that word (instead of "feo" which, as I recall, was the universal insult). So, are you saying that during P.E. you tried over and over to hit me with a tennis ball? I'm not sure how I feel about that!

Anonymous on Wed Jun 14, 07:24:00 PM:

You have made me laugh. So much. Or mucho. I had never realized how many articles plus nouns "Blanca Nieves" has. La bruja, el duende, el espejo. I hope el juego was muy divertido. Great post, Alice!

Katy on Fri Jun 16, 09:35:00 AM:

Alice, I love the title of this post. Do I get points for getting the reference? Probably not, considering your audience.

It's not quite the same, but I like to use my mild astigmatism as an excuse for my clumsiness. I actually do have some problems with it when I'm walking around in my astigmatism-correcting glasses and my peripheral vision is all distorted relative to what I can see straight ahead. Maybe I can get Oliver Sachs to do an article about my daily struggles to walk down the very long escalator in the T station near my house.